Evaluation of the fertilizing effect of olive mill waste compost in short-term crops

Recycling to soil Olive Mill Waste (OMW) has the potential to improve soil fertility, thus reducing CO2 emission associated to global warming. However, the short period in which OMW are produced and the high load of recalcitrant compounds, make difficult direct land spreading of raw OMW. Consequently, sustainable biological treatments able to transform OMW into a safe amendment have been progressively developed. In comparison to a standard mineral fertilization, the present work assessed the agronomic performance of two innovative kinds of OMW compost, used as fertilizers in Lactuca sativa and Lycopersicon esculentum cultivation trials. Both crops showed yields comparable to control, thus suggesting that most of the nutrients contained in the OMW supported adequately plant growth, even in short-term crops. Six months later OMW application, no significant differences were found in the soil humic content.